Pwm Limits - Siemens SIMATIC S7-1200 Function Manual
Pid control
Hide thumbs
Also See for SIMATIC S7-1200:
- Manual (364 pages) ,
- System manual (338 pages) ,
- Reference manual (89 pages)
Table of Contents
Advertisement
6.2.4.2
PWM limits
The PID output value PidOutputSum is scaled and transformed via a pulse width modulation
into a pulse train that is output at the output parameter OutputHeat_PWM or
OutputCool_PWM. The "Sampling time of PID algorithm" represents the time between two
calculations of the PID output value. The sampling time is used as time period of the pulse
width modulation.
During heating, the PID output value is always calculated in the "Sampling time of PID
algorithm for heating".
Calculation of the PID output value during cooling depends on the type of cooling selected in
"Basic settings Output":
● If the cooling factor is used, the "Sampling time of PID algorithm for heating" applies.
● If the PID parameter switching is used, the "Sampling time of PID algorithm for cooling"
applies.
OutputHeat_PWM and OutputCool_PWM are output in the sampling time PID_Temp
(corresponds to the cycle time of the calling OB).
The PID algorithm sampling time for heating or cooling is determined during pretuning or fine
tuning. If you set the PID parameters manually, you will also need to configure the PID
algorithm sampling time for heating or cooling. The PID_Temp sampling time is equivalent to
the cycle time of the calling OB.
The pulse duration is proportional to the PID output value and is always an integer multiple
of the PID_Temp sampling time.
Example for OutputHeat_PWM
①
②
③
④
PID control
Function Manual, 03/2017, A5E35300227-AC
PID_Temp sampling time
PID algorithm sampling time for heating
Pulse duration
Break time
Using PID_Temp
6.2 Configuring PID_Temp
171
Advertisement
Table of Contents
